The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The present trend in power converter technology calls for increased power density with little or no compromise in efficiency. Accordingly, circuit elements such as synchronous rectifiers and ORing MOSFETs, due to their efficiency, are important to power converter design.
However, these circuit elements can be damaged when they are employed in power converters that are susceptible to reverse current. For example, a bus converter typically includes two or more power converters (also referred to as power supply modules) coupled to an output via a bus. Reverse current can flow in one or more of the power converters if, for example, the output voltage of one power converter is greater than the output voltage of another power converter. Further, reverse current can flow in a power converter having an output connected to a voltage source, such as a battery or a capacitor bank. Also, reverse current can flow in a power converter that is operating at no load or minimum load (e.g., less than 10% of rated load). In addition to possibly damaging circuit elements, reverse current generally degrades power converter performance.
In order to protect circuit elements such as synchronous rectifiers and ORing MOSFETs from reverse current, some power converters employ a comparator to compare a current sensor output with a reference to determine whether a particular synchronous rectifier should be deactivated. The current sensor can be a resistor, current transformer or Hall Effect sensor. These sensors, however, can decrease the efficiency of the power converter.